ajax对于来自spring控制器的大量数据返回null

Question

I try to return data from controller to AJAX success() callback. This code perfectly works for 100,000 objects. But when I increase size of list to 1 million objects, it goes to success() callback, but returning null as response. Could you help me with finding the way to return 1 mln of objects?

  A.$.ajax({ url: 'getData', dataType: 'json', success: function (response) { alert(response) } 

 @RequestMapping("/getData") public @ResponseBody void download(HttpServletResponse response ) throws IOException, JSONException { List <Objects> list = getListFromService(); response.setContentType("application/json"); PrintWriter out = response.getWriter(); ObjectMapper mapper = new ObjectMapper(); String jsonString = mapper.writeValueAsString(list); out.print(jsonString); out.flush(); } 

Answer 1

Your method is annotated with @ResponseBody but it's return type is void. Try to return your List directly, and let Spring handle the JSON processing for you:

@RequestMapping("/getData")
public @ResponseBody List<Objects> download( ) {
    return getListFromService();
}

Answer 2

There is a limit set by server and the spring too probably. Check this link .

In such case you should mostly see error in the logs for the limit being exceeded.